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Key facts

What is cataract?

The lens of the eye is normally clear. Light passes through the lens to the light sensitive tissues at the back of the retina, to form an image. A cataract forms when proteins in the lens become damaged. When a cataract develops, the lens becomes cloudy and prevents light from reaching the retina, resulting in blurred vision. In its early stages, a cataract may cause a lessening of vision but eventually it can cause blindness if left untreated. Cataracts usually develop slowly and at different rates in each eye.

What are the risk factors for cataract?

Most cataracts are due to ageing. By the age of 80 years, it is common for people to develop or form some cataract. Other risk factors include:

smoking cigarettes

exposure to the sun

diabetes

injury to the eye

a history of severe diarrhoeal infection

some drugs

family history

What are the symptoms of cataract?

Symptoms of cataract can include:

blurred vision

sensitivity to light (glare)

reduced night vision

fading or 'yellowing' of colours

double vision or multiple images in one eye

frequent prescription changes in eyeglasses or contact lenses.

How is a cataract detected?

Cataract is detected through a comprehensive eye exam that can include a visual acuity test, dilated eye exam and tonometry. A visual acuity test is an eye chart test which measures how well a person sees at various distances. A dilated eye exam and tonometry need to be carried out by an eye care professional. In a dilated eye exam drops are placed in the eyes to widen, or dilate the pupils and a special magnifying lens is used to examine lens to check for cataract, and the retina and optic nerve for other eye problems. After the exam, close-up vision may remain blurred for several hours. Tonometry is a procedure using a tonometer to measure the pressure inside the eye. Numbing drops may be applied to the eye for this test.

How is cataract treated?

The early symptoms of cataract may be improved with new eye glasses; however, the usual treatment for cataract is surgery. Cataract surgery involves removing the cloudy tissue from the internal part of the lens, and leaving part of the lens capsule behind to act as a support for an implant called an intraocular lens. In most cases only a local anaesthetic (numbing) is needed and the person can go home the same day. Cataract surgery can quickly restore vision and is considered very cost effective.

What is known about cataract among Indigenous people?

A national eye survey in 2008 found that cataract was the second-leading cause of low vision for Indigenous Australians. Cataract was the cause of 27% of low vision and 32% of blindness among Indigenous adults, with vision loss from cataract being more common in very remote areas. Only 65% of those with vision loss from cataract had received surgery. Blindness from cataract was 12 time higher for Indigenous adults compared with other Australians. Some of the main issues affecting cataract treatment for Indigenous people, especially in remote areas are: